Historically emulsified fat system in margarine/spreads has been designed to satisfy customer requirements such as significant cooling impact, a rapid sharp melt sensation, and no coated or waxy feel on the tongue. In addition, it should impart temperature cycling stability (heat stability) as well as spread ability when taken out frequently from the refrigerators is the prominent features.
To achieve these objectives, margarine fat blend is being formulated using hard stocks derived by hydrogenation of liquid oils.
However, with the adverse effect of Trans fatty acids being published, consumers are looking for margarine/spreads with practically no trans fatty acids. Recent studies have indicated that trans fatty acids produced during the hydrogenation process is considered much more harmful compared to saturated fatty acids (SAFA). Low trans fatty acid levels can be achieved by using fully hydrogenated fats as structural fat, which usually does not contain trans fatty acid or very negligible amount. Such hydrogenated fats were subjected interesterification with lauric fats and solvent fractionated to derive premium quality structural fat that could be incorporated in smaller level to produce Low SAFA products.
Hydrogenation process is generally viewed as the main reason for the development of trans fatty acids in oils and fats. Hence, there is a strong consumer perception against usage of and hydrogenated oil/fat in the food products including margarine/spreads/shortening. Further use of organic solvent as well detergent for fractionation process are viewed by the consumers are unhealthy processing.
Hence research work is being carried out for developing margarine/spreads and shortening using no hydrogenated oils in their hard stock at the same time looking at the possibility of reducing the saturated fatty acid levels (SAFA) in the products At the same time work were carried out to develop new fractionation process to eliminate usage of solvent/detergents in the fractionation process.
For manufacturing Margarine/Spreads, the fat blend should be such that it has a flat melt profile from 5 to 30 Deg C. at the same time low solids at 35 and 40 deg C. so that the product has good mouth feel. The blend should be such that the product does not oil out and has good temperature cycling stability.
Further in recent years due to high publicity in the media with respect to adverse effect of Saturated as well as trans fatty acids, many manufacturers have taken a nutritional approach to manufacture the product by reducing the saturated as well as trans fatty acids and increasing poly/mono unsaturated fatty acids in the margarine/spreads as well as shortening.
Margarine/Spreads have been on the market for some time aiming to meet this need. Typically, the margarine fat of these products consists of about 87% liquid oil, e.g. sunflower oil and 13% of a hard stock consisting of a random interesterified mixture of fully hardened lauric fat, e.g. fully hardened palm kernel oil, and fully hardened palm oil.
Attempts have been made over the years to formulate margarine/spread fat blends by using much lower levels of hard stock. For example EP 89,082 recommended H2M rich hard stocks. The preferred method described in EP 89,082 for producing such hard stock is randomly interesterifying a partly or fully hydrogenated lauric fat having a melting point ranging from 30 to 41 degree. C., with a fat, which can be fully or partly hydrogenated, fractionated or non-fractionated, wherein at least 60% of the fatty acid residues are C.sub.16- or C.sub.18-fatty acid residues. This C.sub.16-C.sub.18 fat is preferably selected from palm fat, soybean oil, groundnut oil, sunflower oil, maize oil, and rapeseed oil, having a melting point ranging from 50 to 71.degree. C.; and fractionating the interesterified mixture. Fractionation is preferably done in an organic solvent. The examples of EP 89,082 illustrate spreads comprising margarine fats containing 90 or even 93% sunflower oil and only 7 or 10% hard stock. This hard stock is produced by means of 2-stage fractionation in acetone to obtain a mid fraction of a random interesterified mixture of 50 parts fully hydrogenated palm kernel fat and 50 parts fully hydrogenated palm fat.
Thus EP 89,082 met the objective of manufacture of Margarine/Spreads with very Low SAFA as well as very PUFA/MUFA by producing a hard Structural fat that can be used at levels as low as 4%.
However, recently consumers have been expressing concern about chemically modifying fats e.g. by hydrogenating or hardening, which result in trans fatty acid residues if partial hardening is involved. Also consumers have been voicing their concern over use of solvent such as Acetone etc as well detergents for fractionation of fats. Even though full hydrogenation eliminates the presence of trans fatty acid residues, still there is a consumer perception that any hydrogenated product is undesirable. Because of this the manufacturers of margarine/Spreads have been looking for alternate hard stock, which do not undergo hydrogenation as well as solvent fractionation processes. To meet the need for spreads with low contents of SAFA in the margarine fat which have been produced without using hydrogenation, CA 2 098 314 proposes to prepare hard stock by chemically interesterifying a blend of generally equal proportions of palm stearin and palm kernel stearin.
However the usage level of such hard stock was 14-21% especially about 16% to obtain a good quality product. This high level of usage resulted in higher level of SAFA in the final products. Hence attempts have been made to prepare hard stock that can be used at much reduced levels of even 5 to 14%. This objective was reached to a considerable extent in recent years. For Example in U.S. Pat. No. 5,858,445, U.S. Pat. No. 6,156,370, CA 2207954, as well as in WO 96/19115, the inventers have found that a hard structural fat that can be used at level of 5-14% can be produced with out Solvent fractionation, random chemical interesterification as well as hydrogenation process that has been used in EP 89,082. Accordingly, the invention provides a margarine fat blend essentially comprising 86-95% liquid oil and 5-14% of a hard stock, this hard stock being a stearin fraction of an enzymatically interesterified mixture of 25-65%, and preferably 35-55%, unhardened lauric fat stearin and 75-35%, and preferably 65-45%, unhardened C.sub.16+ fat stearin.
By selecting unhardened natural vegetable fat products having sufficient saturated fatty acids, such as lauric fat fractions and palm oil fractions for the enzymatic interesterification, the chemical modification of the fats were reduced to a minimum and the trans fatty acid level in the final fat blend were to almost zero.
The hard stock produced from un-hydrogenated fat under U.S. Pat. No. 5,858,445, U.S. Pat. No. 6,156,370, CA 2207954 and WO 96/19115, could achieve quite similar results with respect to the nutritional properties of the spread as in EP 89,082. How ever EP 89,082 focus on fully concentrates on achieving the minimum SAFA content in the product with acceptable product properties and heat cycling stabilities. To meet this requirement, the inventors used all the fat modification techniques including hydrogenation, chemical interesterification, solvent fractionation and even chemical synthesis of triglycerides.
By using Structural fat produced under U.S. Pat. No. 5,858,445, U.S. Pat. No. 6,156,370, CA 2207954 and WO 96/19115 the inventers could substantially match the performance of EP 89,082 without using Hydrogenation, solvent fractionation, and chemical interesterification. However to achieve this, they had to resort to expensive multi stage dry fractionation process as per EP 399,597 to produce hard palm C16 fraction. Further, they had to use expensive enzymatic interesterification process for interesterification of Lauric fat as well as palm fat. Further, the interesterified fat was required to undergo an additional dry fractionation process at 31-41 Deg C. to produce hard Structural fat for use in margarine blend. Solvent fractionation process improved the yield of the hard fraction but is considered very expensive and not natural because of usage of solvent in the process. Such solvent fractionation plant are highly capital intensive and require very high safety and environmental feature. This, however, resulted in low yields of structural fat ranging from 14 to 45%. Since this process produced excessive olein fraction (liquid fraction) as a byproduct, alternate use for olein fraction need to be found to get economical value for such fraction. This resulted in the process being commercially un-attractive. Further, inventors used enzymatic interesterification method. To date, the cost of immobilized enzymes required and high capital and variable processing cost involved has made this process un competitive with respect to chemical random interesterification process. This is especially true in case of manufacture of low value products like fats for margarine/spreads/shortening.
Further, many consumers do not consider enzymatic interesterification as a “truly” natural process. For example, in recent EU Parliament directive No. 20000/36/EC of 23 rd Jun. 2000 relating to cocoa and chocolate products intended for human consumption, has prohibited use of vegetable fat which has under gone “enzymatic” fat modification of the triglyceride structure. Further, many of the new enzymes are produced by genetic modification and there is again very strong consumer perception against products derived using genetically modified substances.
We, therefore, consider random chemical interesterification process is more “natural” and a mild process as the alkaline metal catalyst, namely, sodium methoxide used in the process breaks down as sodium hydroxide. Sodium hydroxide has been used historically and even to day for the refining of soft oils such as soybean, sunflower, canola etc and such refined oil is consumed widely and even for manufacture of margarine/spreads. Further, chemical interesterification is a well known art in the industry and needs low level of technology and cost.
We, therefore, found that this economic and commercial issue involved could be addressed by inventing a new process to manufacture hard palm fraction that could be interesterified with a hard palm kernel fat. We wanted to avoid further fractionation steps of such interesterified fat so that the yield of structural fat is approx 97%. Even if, a further fractionation step was required to produce extra hard structural fat, the focus was how to improve the yield of such hard stock to level of 65% and above compared to 14-45% that were achieved under U.S. Pat. No. 5,858,445, U.S. Pat. No. 6,156,370, CA 2207954 and WO 96/19115.